Haven’t done much in the past few days, mostly because I’ve had the workbench cleared off to fix a recalcitrant robot vacuum. I did unroll some of the plans and take a good long look at the tail surface sheet. Sixteen feet or so of paper, mind you… not the easiest thing to manage on a 6′ countertop! I wish that had been split into two sheets.
It looks like I can build the entire fin and rudder out of pine and plywood, so that’s my next project, I think. I’ll go look for a suitable 10′ length of pine at Menard’s that can be ripped down into decent quality lamination strips. Once the saw is set up for that I’ll make as many as I can, since I’ll have a bunch of other laminations to do as well for the wingtips and fuelage. Then I’ll look at what to do for the elevator and stabilizer spars.
I’ve knocked out a few more aileron ribs, two at a time. I’m about halfway through them and trying to speed things up a little, so I don’t die of old age with a half finished airplane.
Yesterday I decided to use up a piece of obviously bad capstrip Aircraft Spruce saw fit to ship me. This piece has a large chunk missing out of one edge, part of a knothole or pitch pocket or something. Part of it is in no way suitable for aircraft use or much else for that matter. But – there’s enough good wood there to use it for false ribs, so I made one of those. That went OK, but it’s apparent that I will need to soak the top capstrip in HOT water for the false ribs.
I’m looking forward to starting work on the tail surfaces. I’m planning to get out to the garage and clear off the workbench this week, lay out the plans and see exactly what I will need to get started. The wood called out is white pine, so I’ll start checking the local places for suitable pieces of white pine or Douglas fir… a little heavier, but I know Menard’s sells some good boards from which I can cut suitable pieces for the laminations.
I emailed Dave at Fisher Flying Products asking about the lift struts I have seen used on several Celebrities that I’ve seen in pictures. I still have not seen an actual Celebrity “in person”, nor any other completed Fisher design for that matter – just a partially built single seat ultralight at Oshkosh. It seems you have a choice between lift struts or flying wires. Personally, I like the look of flying wires a lot better. It just has that classic wire-braced biplane look. I know that a cylinder shape, such as a wire, has much higher drag than streamlined tubing. A cylindrical object will have 10 times the drag of a streamlined shape of the same frontal area. The wires, however, will be much thinner than struts, 5/32″ — meaning that they would produce drag roughly equivalent to 1-9/16″ wide streamlined struts. BUT… the plans call for 1-1/8″ and 1-1/4″ round tubing for the lift struts. The flying wires would have far less drag than those. I could probably replace the round aluminum tubing with smaller streamlined steel and pick up some drag reduction there, but the fact remains — I just don’t like the look of the lift struts.
It’s not like this airplane will be a speed demon no matter what I do, so I’m not really worried about what may be a small drag penalty for the wires. If I wanted to fly faster and more efficiently without regard for anything else, well, I have an RV-12 for that (acknowledging that “faster” is entirely relative here). It looks like I can have the wires made to my specs by Aircraft Spruce, swaged and tested with professional equipment so I don’t have to worry about getting it perfect on my first try.
I did some additional work on the rib jig yesterday, including installing the main spar locating block and cleaning up a few nail points that were poking out the bottom. I cut a bunch of blocks to locate the outer shape of the ribs, but did not install them yet. I want to wait until I have some spruce stock to put in place, so I make sure it’s all in the right place. I really want these to turn out as close to perfectly consistent as possible. I had planned to use some pine cut down on the table saw to set up and test the jig, but it occurred to me that I had no way to know for sure my pine strips would be the exact same size as the capstrip stock supplied by Aircraft Spruce. So, it’s time to order some wood.
I spent some time yesterday working on the first wing rib jig. The workbench needed a new top surface, so I picked up a sheet of 3/4″ MDF at Lowe’s. They were nice enough to cut it for me. I ended up with one piece 3′ x 8′ for the bench, and two 1′ x 4′ chunks for rib jigs. Nice how that worked out.
I marked a center line on the MDF and laid out the rib setup from Sheet #1 of the plans over it, then trimmed the paper to fit the jig. I hate cutting up plans, but there’s an extra copy of that page for this reason. I made all of the little chunks of plywood for the locating blocks, and cut a few small pieces of pine stock as needed. Then I cut out the places where I would need holes to accommodate clothespins, marked those on the MDF and cut them out with a scroll saw. I used some spray adhesive to stick the plans down to the MDF. So far so good.
Next I had to find some clear poly to cover the plans sheet. I finally remembered the nearly 4′ long bag in which the plans were shipped; it fit just fine. With that in place I started nailing the locating blocks in place over the plan sheet. I got most of them done before knocking off for the night. I still need to make one more plywood block for the main spar locator, and make the blocks for the top and bottom capstrips. I haven’t decided for sure how to do those. I had thought about using a couple pieces of pine bent to fit, but that seems like a great way to mess up the jig trying to get them perfectly in place, and the jig needs to be as close to perfect as I can make it. I’ll probably go with closely spaced pine blocks, nailed in place.
I received a quart of T-88 epoxy yesterday, so the first batch of glue is covered. Today the mail carrier brought the plans, tightly rolled and somewhat bent from their trip from the nether regions of Canada. I will be building Celebrity serial number CE164. So now I have a number of jobs that need to be completed…
- Get the plans unrolled to flatten out so they’re usable
- Get an inventory of the drawings, figure out how and where to store them so that they’re protected. I may add tabs or some sort of externally visible identification so I’ll be able to quickly locate a drawing. One of the irritations encountered while working on the RV-7 was sorting through a pile of drawings to find the one I was looking for. That was a time waster. These drawings are in at least four or five different sizes, a few of them 16′ long. Fortunately, it does not SEEN as though I’ll need to frequently switch between several drawings as I did while building the RV.
- Replace the workbench top with fresh MDF. It’s a good solid bench, but the old hardboard top is scrap. As a bonus, a 4×8 sheet of MDF will be one foot wider than the bench, giving me a 1×8′ cut-off. That will make two 1×4′ wing rib construction jigs.
- Figure out where to begin construction.
- Order up some wood!
I’ll start with the wing ribs. They use only two sizes of stock, and construction is simple and repetitive. I can build the first two or three out of locally sourced pine, just to get the jigs built and get my process sorted out. I can scrap them or use them as wall decorations in my office. The jigs do not need to occupy the entire work bench, so the bench can be used for other things while working on the ribs.
I don’t know where all this will lead. Maybe I’ll end up building and flying a new airplane. Maybe I’ll end up with some interesting wall decorations. All I know is, I feel the need to explore this and see where it goes. Yesterday I ordered a set of plans for a Fisher Celebrity.
I’m already thinking about various modifications… mostly trying to de-drag some of the structure by using streamlined tubing or even wood for struts and such. And I’m keeping an eye out for possible engine choices. I’m kind of torn on the whole electrical system question. part of me says keep it light and simple — no electrical system, no transponder, handheld radio. The other part doesn’t want to have to hand prop the engine.
We’ll just have to see where it goes. Who knows? Maybe I just end up making really cool looking furniture and never finish it.